Passive auxiliary injection circuits for pulse tripling in three parallel-connected rectifiersOA

This paper proposes two types of passive auxiliary injection circuits(PAICs)that enable pulse tripling in three parallel-connected rectifiers,addressing the limitation of pulse multiplication to a factor of 2.The proposed design combined three rectifier units with two PAICs consisting of a delta/star transformer and nine auxiliary diodes.By further integrating the PAICs with conventional topologies such as 3-pulse star,6-pulse star,6-pulse bridge,18-pulse star,and 18-pulse bridge rectifiers,we constructed 9-pulse star,18-pulse star,18-pulse bridge,54-pulse star,and 54-pulse bridge configurations,respectively.The validation in MATLAB/Simulink demonstrated that these configurations achieved a threefold increase in both output-voltage pulses and input-current steps without the need for complex phase-shifting transformers.Moreover,the total harmonic distortion of the input current was significantly reduced,with values of 12.63%,3.66%,3.43%,2.24%,and 1.90% for the respective designed rectifiers.To the best of our knowledge,this is the first demonstration of a passive pulse-tripling circuit for three parallelconnected rectifiers,offering a simple solution for high-current industrial applications.